Springless firing valve



Feb. 23, 1965 Filed July 9, 1962 A. G. JUILFS ETAL 2 Sheets-Sheet l Je 4? df 42 54' 4a 74 gs 4m `WJ 29 /1 45% had k Ha' Il ,5 26 /0 INVENTORS. Bser G. JUIL/rs, CARL ECHT BY W, hm, ft

:rr-roanne Feb. 23, 1965 Filed July 9, 1962 A. G. JUILFS ETAL SPRINGLESS FIRING VALVE 2 Sheets-Sheet 2 ATTORNEYS uns@ United States Patent O This invention relates to a springless pressure valve, and more specically, to such a valve rdisposed to control the Vflow of fluid into a driving or working cylinder.

In its broadest terms, this invention will have utility any time it is necessary or desirable to control the iioW of a fluid under pressure. However, and for purposes of illustration only, the invention will largely be described as employed with pneumatic Staplers and nailers where it has been found to have great particular utility. In such an application, the valve of this invention serves to control the iiow of iiuid power into the working or driving cylinder of the device. But it is to be understood, and for that reason emphasized at the outset, that none of these factors is to be considered a limitation on the invention,V except as specifically set forth in the claims following this disclosure.

In the case of the conventional valve which is spring biased to its closed position, and which is opened either manually or by the action of uid pressure, speed of operation will vary over a considerable range depending on `the pressure used. In other words, for any given spring, the greater the pressure, the faster the valve will open, and the lower the pressure, the slower the valve will open. This is particularly important in the case of a firing valve, since a quick acting valve will deliver the iluid power to the driving or Working cylinder much more rapidly, and thereby obtain more power in the working stroke. Since pressures available in commercial operations Will vary considerably and since springs also vary considerably, undesirable variations in the speed of valve operation will occur in these prior devices.. Herein lies one of the greatest merits of this invention. Since the valve hereinafter disclosed is actuated solely by'pressure voperating pressures.

To aid in fully and completely-understanding the operation of the instant valve in its specific applications to a pneumatic stapling device, a brief analysis of the prior art background will bevery helpful. These comments will necessarily be somewhat generalized; if desired, a full and complete disclosure of one type of pneumatic stapler may be found in US. Patent 2,983,922 issued to A. G. Juilfs on May 16, 1961. Basically, such a device comprises a remote control valve, actuated by simple trigger, which serves to actuate a tiring valve. This firing valve in turn controls the flow of pressurized air into the driving or working cylinder. When the remote conthe piston and driver may return to their initial position.

Early devices operaing on this principle included springs or similar mechanical devices, servingboth to return the driving piston to its originalv position and to; return the ring Vvalve to the closed position. In the interest Vof ginning of the return stroke. f

3,l7,487 Patented Feb. 23, 1965 ICC operating eiciency, it was later found desirable to eliminate as many of these springs as possible. A major step forward occurred with the development of a means for utilizing the pressurized air to return the driving piston to its original position. While this stepsounds relatively simple, it will be obvious to one skilled in the art that it increases many fold the diliiculties of timing and the complexities of the valve structures required. In other words, as a pressurized iiuid is introduced to the driving cylinder above the driving piston, the area in that cylinder below the driving piston must be provided with an exhaust port which will permit the fluid beneath the piston to be expelled as it moves downwardly. To effect a return of the piston, these exhaust ports must be closed, andpressurized i'iuid must now be introduced to the cylinder beneath the driving piston; and of course, means must be provided to exhaust the pressurized air which is now in the driving cylinder above the piston. The valving and timing problems of such a device are so great that it is characteristic of all prior devices that at some point in their cycle, both intake and an exhaust port will be open at the same time, with the consequent loss of air.

Accordingly, it is a primary object of this invention to provide a springless valve tocontrol thellow of a pressurized fluid into the driving or working cylinder positively and accurately irrespective of the .pressure used.

An equally important object of this invention is the provision of a firing valve of such a construction that at no time in its operating cycle are the exhaust and intake ports open together.

A further object of this inventionis to provide such a valve adapted for use-'in a pneumatic stapler which used as minimum amount of air even though the driver actuating piston is both driven and returned by air.

A very important object of this invention is they provision of a springless tiring valve for a portable pneumatic stapler' such that the eiciency of the stapler will be greatly increased.

Still another object of this invention is to provide a springless tiring valve for a portable pneumatic stapler which will result inl substantially trouble free operation, and which may be easily replaced in the event thata defect should occur. y

These and otherobjects of the invention will be readily apparent to one skilled in the art after reading this specification and examining the accompanying drawings. For purposes of illustration, the invention is shownas applied to a portable pneumatic stapler, and the same I reference'numerals have been employed to designate similar partsthroughout the several views. 1 y FIGURE l is ,a fragmentary cross-sectionalfview,"show ing the original position ofthe various components.

FIGURE 2 is also a fragmentary cross-sectional view sirnilar to the top portion cf FIGURE 1-, showing the position ofthe tiring valve just prior to the beginning of the driving stroke.

FIGURE 3 is a fragmentary cross-sectional view similar to FIGURE l indicating the position of the firing valve at the initiationof the driving stroke.

FIGURE 4 is a fragmentary cross-sectional view-showingthe various parts at'th'e end of the driving stroke.

FIGURE 5 is a fragmentary cross-sectional view showing v'thedriving mechanism and tiring valve at-the fbe- FIGURE" 6 is a fragmentary cross-sectional view showing only the firing valve and the driving mechanism towards the end of the return stroke of the driving mech-V anlsm.

As noted in the foregoing preambular comments, the firing Valve of this invention isactuated entirely by force and pressure differentials. of the invention, amplification of these comments by way of brief description of the operation of the device is appro# priate at this point.. And once again, it should be pointed out that'while the description is made in terms of a pneumatic stapling device, this is exemplary only, and should not be construed asa limitationof the scope of this invention. `The contemplated firing valve comprises a valve chamber, one end of which communicates with the lworking or driving cylinder of the stapler; T he other end of the valve chamber is provided with a fixed center l post, the lower end of which is of a larger diameter than the upper end. Both an air inlet and an exhaust port rnust be provided near each end of this chamber. Within this chamber is a movable valve element adapted for reciprocal movement over the fixed center post. This will mean that the upper portion of the valve element' v must be provided with Va bore of the same size as the upper end ofthe fixed center post, and the lower end of the valve element must be -provided with a bore `of a larger diameter-a diameter equal to that of the enlarged end of the fixed centerpost. Sealing means are provided between each portion of the center post and its mating bore in the valve element. rhis construction results in a surface area differential, so that when the same pressure is applied to. bothV ends ofV the valve element, it is urged -in .a direction away Yfromfthe end having the larger area,

which in this casewould be downwardly.V

The operationof the valve when embodied in a pneu.- maticstapler is as follows. The stapler will Ybe connectedto any conventional source of pressurized air. With the various components inV .theirl original position, the air inlets in both ends ofthevalve chamber are open and in communication with this source of pressurized airso that under the influence of the area differential, the valve Since this ls a crucial aspect.k

. are exactly reversed.

driving it into the workpiece.A Conventional meansmay be provided for holding a plurality of staples and placing them successively beneath the stapledriver.

` To complete the operatingcycle, the above procedures In other words, as the trigger is released, the remote control valveY will` first close the exhaust port inthe upper end of the Vvalve cylinder.

Further movement of the remote control valve willopen element is urged to the closedv position; that is, the port.

leading from the valve chamber to thedriving cylinder of Vthe stapler is closed. Also at this time, the exhaust port in the lower endof the valve cylinder (which also serves to exhaust the driving cylinder) is open to the atmosphere. f

Upon actuation of the trigger, the first step isitoclosei thel air inlet leading to the upperend of the valve chamber. Y

This is accomplished by means of a remote control valve f which will be more fully described hereinafter. )Further vmovement of the trigger results in la further movement of -V this remote control valve which in turn opensthe exhaust port in the upper end of the valve chamber to quickly exhaust the pressure applied to this end of the valve element. When the total force applied to the lower end of this valve element (larger pressure applied to the smaller area VVcany overcome the total forceapp'lied to the upper end of this 'element (this upper end now being open to exhaust), Vthe Valve elementwill be Vmoved upwardly.

By means of the novel and/uniqueconstruction of this valveelement, the upward movement accomplishes twoV very important functions,-and furthermore carefully controls the timing Vsequence' of these operations.`

The 'rst fraction of an vinch of. upward movement of the valve element closes the exhaustrport in they lower end of the valve cylinder. As was` noted earlier, Ythis sameV exhaust port ,alsoservesl to exhaust Vthe driving cylinder duringV the return stroke ofthe piston therein, but'tha't stage ofthe operation will be'considered ata later point.

f The remainder ofthe upward vmotion of thevalve'.

elementiresults in the Vvalve lifting off and thereby openv .ing the passageway leading tothe driving cylinderof the stapler. ,With this ,passage open, the pressurized'air.. rushes l "finto the. cylinder, driving the piston and *staplefdriver downwardl'y, whereupon `the 'driver will engage a staple",l

, driving cylinder.

Y l1, and `a nose portion Vshown at l2.

understood that the staplerfwill include means `orstorthe air inlet in the upper end of the valve chamber, thereby permittingrthe'full force of the pressurizedl air to act upon the top surface of the lvalve element.` As explained above, since thistop surface area is larger than the bottom surfacearea of the valve element, equalpressure applied to bothends will result in its downward movement.

Once again, the downward .movement performs two very important functions, and also serves to control their timing. The valve element will move down until it first closes Vthe .port leading from the valve chamber to the ment of the valve element will open the exhaust port in the lower end of the valve chamber. .This willthen permit the pressurized air above the pistongin the driving cylinder to escape to atmosphere, and the piston and driver may be returnedto their original position, by any suitable means, ln the particular embodiment shown, we have provided an air reservoir around the driving cylinder, and again utilize pressure differentials to effect the return ofthe driving piston.

lt is believed that the Vforegoing brief description will clearly illustrate the primary objects of this invention. n In the first place, there are absolutely no springs in either the `remote control valve or the firing valve. Both the firingV valve which is theY subject of thisfapplication, and

the driving piston are actuated entirely'byforce and pressure differentials. The remote'control valve is actue fated manuallyV and returnedV by air pressure. Secondly, and very important, is the timing ofthe device whichv insures that at no time in the operating cycle ofreither the firingrvalve or the remoteV control valve are both an exhaust port and an intake` port open together.Y For example, inythe area of the valve chamber above the valve element, the first movement of thel trigger and the remote control valve closes the air inlet; further movement will then open'the exhaust port. And in the reverse cycle, the

exhaust port will b e Aclosed before the air ,inlet is' open again'.VV Andin the case of the areaofthe valve chamber Vbeneath. the valve element, the exhaust port will be closed ing and feeding staples into'the nose section l2; many satisfatcory devices 'for .this-purpose.V are available, and

' sincejitV formano part of theinstant invention, thisV storing means has `not been shown in any ,ofthe and rvfeeding figures.

.The motive power Vfor this' device is Vobtained from any f suitable source of air yunderpressure..` The ordinary shop air line will deliverairfat a pressure Vof about v to pounds per'square inch; however, .itis Vnoteworthy that :this invention will Yoperate equally ,Well over a very wide'V range of airpressuresf Thehandle portionV loof y the staplerlisfprovided withzafhollow chamber 3.3 com- Y jrnunicating'with ,the air supply. Theair chambenl is provided YwithtwoV ports, ll/land l5, ir/l'liclrV communicate AjV withV the .upper and lower.l ends. ofthe;valveachamber rel'- spectivelyl. '.The` port .lf-iis always open, anddefinesan extension of Ithe chamber lf. 'lfhe ilo-wreffairjthrough- And then, further downward rnovefk the port 14 is controlled by means of the remote control valve which includes a valve body or sleeve 16 which is threaded into they handle portion of the stapler. A

Vrubber O-ring 17, or other suitable sealing means, in-

sures an air-.tight -it between the valve sleeve and the stapler housing. At its upper end, the valve sleeve 16 is provided with a port 19 which, through the port 14, is in communication with the supply of pressurized air in the chamber 13. The valve body is also provided with a plurality of ports 20 annularly spaced about the valve sleeve and'opening into a passage 21 formed in the stapler housing. Within the valve sleeve 16 is a movable plunger 22 having a sealing means 23 with a relatively flat face which is wider than the ports 20. This plunger 22 is adapted to reciprocate within the valve body l16 under the urging of the manually operated trigger 24 1n one direction, and under the urging of air -pressure in the opposite direction. A cap 18 threaded into the stapler housing serves to retain the .plunger 22 against the varr pressure entering through the ports 14 and 19. Initially, the parts will be inthe 4position indicated in FIGURE .1. That'is, the :plunger 22 is in its lowermost position in which the flange 25 abuts against the plug 18. In this position, it will be noted that .the member 23 is below the ports 20 in the valve body. This means that the pressurized air in the chamber 13 hows through the ports 14 and 19 into the sleeve,and then through the ports Ztl into the passage 21. The small tube indicated in the drawings at 26 serves to connect the passage Z1 with the ypassage 27 also formed in the stapler housing. The passage 27 in turn communicates with the upper end of the firing valve through the port 25.

Still referring to FIGURE 1, the various parts of the ring valve will now be described. The Valve chamber is formed in the upper part of the body portion 11 of a stapler. It terminates at its lower end in a valve seat 29, and the upper end is closed by a cap .30. As is clearly shown in the drawings, the cap 3) is provided with an annular wall 31 which extends down into the stapler housing. The sealing rings 32, or other suitable sealing means, insure an airtight lit. in position by any suitable means (not shown) in the main body portion 11. of the cap is a cylindrical hollow post 33,j The post 33 terminates in an exhaust valve 34, which is securely held in place by means of a bolt such as shown at'SS. The spacing member indicated at 36 extends from the lower end of the walls 31 to the valve seat 29, and serves to hold the latter element in place. y

The moving valve element has been indicated generally at 37 inFIGURE l. For the sake of clarity, this particular element can probably best be understood by referring at this time to FIGURE 6. It will be observed that the valve 37 is closely fitted within the cap walls 31, ywith the resilient 0ring 33, or other suitable sealing means, insuring a satisfactory seal. The valve 37 is provided with a hole 37a in its upper end which is Slidably engaged over The cap 36B may be secured Securely fastened in the center the center post 33, 'and sealedvby means of theo-ring 39 or other suitable sealing means. Similarly, it should be noted that the lower end of the valve k37 is provided with a hole 37b of slightly larger diameter than the, hole 37a 'in the upper end of the valve. And furthermore,they exi haust valve 34 is adapted to seat itself vwithin this latter hole, the O-ring 140 or other suitable sealing means, furbody 37,.butY is movable longitudinally with respect to the valve Ibody a veryl short distance. The importance of this factor will be explained shortly. Returning now for a moment to FIGUREV l, it has alf ,ready been pointed outthat the air chamberdS is'proj videdywith a port 15; it will now be apparent that this port 1S is in constant communicaion with the lower portion of the valve chamber and valve element 37. As will now `be explained more fully, this pressurized air is acting on only a very small surface area. The various members have been so constructed that, see also FIG- URE 6, the diameter of the valve element 37 at the point 42a of the shoulder 42 is very slightly greater than the diameter of the rubber insert 41 at its largest part 41a. Therefore, while part of the air pressure, is acting to force the rubber insert 41 downwardly to seal against the valve seat 29, the resultant force (considering at this time only the pressure [from port 15 acting onpinsert 41 and shoulder 42) will be upwardly. But at the same time, it will be understood that the pressurized air traveling through the ports 14, 19Vand 20, the passageways 21, 26 and 27, and the port 28 into the valve chamber is bearing upon a considerably larger surface area of the valve element 37. As noted before, therefore, this will result in forcing the valve body 37 downwardly which, of course, will effect a seal between the valve seat 29 and the rubber insert 41. As is clearly apparent from FIG- URE l, the hollow center of the valve element 37 is in communication with the atmosphere by means of the ports 43. As will be explained hereinafter, this serves to exhaust to atmosphere the air from the driving cylinder on the return stroke of its piston; the cowl 44 merely serves to direct this exhaust forwardly.

Fixed within the body portion 11 of the stapler is a sleeve 45, which forms thekwall of the driving cylinder. Mounted -within the lower walls of this sleeve is a reA silient bumper 46 which is relieved around its periphery as indicated at 47, and which serves as a piston stop.

Slidably mounted within the cylinder sleeve 45 is a piston 45 to which is firmly secured a staple driver 49. Preferably the driver 49 is connected to the piston 48 by means of a pin 5t?.

Surrounding the driving cylinder is an air storage chamber 51 delined by the cylinder sleeve 45 and the main body section 11. The sleeve 45 is provided with `one or more ports 52 which, as seen in FIGURE 1, lie immediately above the piston stop 46. These ports are always open. Also located in the sleeve 45, but a short distance above the ports 52, are one or more other ports 53;v these ports are normally closed by means of the reed 54and the valve 55. w

The skilled worker in the ar-t will of course understand that the operation of such a device is extremely fastso fast in fact, that the limiting factor is the speed of the operator and not the capacity ofthe tool. Notwithstanding these very high speeds of operation, the timing of the device is critical. Therefore the step by step operation of the device will now be described. Again, it must be remembered that while the description of such operation sounds slow, the actual operation is very fast. As explained earlier in the specification, with the parts in the position shown in FIGURE 1, the air may travel as indicated by .the arrows. That is, air

Amay pass through the portsV 14, 19 and Ztl, through the passages 21, 26 and 27, through the port 2S, into the valve chamber above the valve element 37. -At the same time, air kcan pass through the port 15' into the valve chamber adjacent the lower part of the valve element l37. Again, as explained before, the greater exposed surface area at the upper end ofthe valve velement 37 will result in its downward movement, which in turn f been compressedabove the valve element 37 may now U 21', and go through the ports Ztl, where it is`permitted .to escape around the Vplunger ZZ by means of the exhaust grooves S6 and 57 in the sleeve 16 (see alsoTIG- URE 3). The pressure previously applied to the upper end of the valve body 37 is now exhausted to atmos-r phere. The resultant upward pressure of the air acting on the shoulder d2, which hasbeen previously described as'larger in diameter than the member 41, will now -move the. valve element 37 upwardly.

As shown most clearly in FIGURE 2, the rubber insert 4l will remain in place while the Valve body 37 is moved upwardly a short distance. Since the exhaust valve 34 lis stationary, the effect of this first upward movement of the valve element 37 is to seal the exhaust ports 43 by bringing the VO-ring 40 intocontact with the valve 3d. Continued upward movement or" the'valve element 37 will lift the member 41 off the valve seat 29, thereby opening this port and permitting the pressurized air to words, .the valvebody 37 is not driven upwardly by the continuing force of the pressurized air, but by the kick it receives as the etective surface area to which the pressurized air is applied suddenly increases. This permits the full force of the pressurized air entering at to be exerted against the piston 48, driving'it downwardly. FGUREY 3 shows` the relative positions of the various. parts just after the rubber insert 41 has lifted off the seat 29. f

As the piston 4S moves downwardly, the air beneath it is forced out through the nose of the stapler alongside the driver (t9.

FIGURE 4 shows the parts as they will be positioned when the piston 4S has reached the bottom of the driving stroke and rests against the stop 46. In this position,

the vports 53 will be above'the top edge of the piston 43, and, under pressure .of the air, the valveSS will be open, permitting theV air to` flow into the chamber l.V Air will continue to passV through the ports 53 against the resistance ofthe reedSd until the pressure in the chamber Si is substantially equal-to the pressure in the driving cylinder itself, whereupon the reed `5ft will vcause the valve 5S to close.

To completev the operating cyclejthe above steps must be substantially. reversed. This islaccomplished uponV release of the trigger 2.4 by the operator. As the trigger 24 moves downwardly,.the plunger 22' will also move downwardly under the yurging of they pressurized air flow'- ing through the ports 14 and i9,`as shown in-'FIGURE V5,. As it moves downwardly, the member 23 willrst surized 'supplylof air. As indicated by the arrows in.` HGURELS, the.. pressurizediair mayonce again `flow i into the valve chamber. above the valve element vf.

valvev dbproducesa resultant downwardl movement, which will onceagain eiect a seal between thev rubber insert 41' and the valve seat 29. Atthis point, the rubber 4insert .will Vremain stationary, but the valvefelement.

37 itselfY continues itsl downward movement a short distance; this.'` last, `"short downward stroke of the valve element 37 will then break the seal-between the O-ring i 'States Letters Patent ist' .theports d3 and out ofthe stapler'to atmosphere.y Final downward movement ofV the element 37 terminates whenV noted that the ports 52 are located Aat'just theupper edge v `of the piston stop. This means ythat the air whichhas been compressed into the reservoir 51 may'now act upon the underside of the piston 48 inthe area exposed by the relieved portions 47 of the piston stop. And once again,

Vwhen the total force on this small surface area overcomes the downwardV force exerted on the top ofthe piston `(as the air above the piston exhausts to atmosphere), the

piston will lift oit yits stop 46. Once again, the eiective surface area on which Ythepressurized air vmay act is then suddenly and greatly increased. Y The resulting kick is suicient to return the piston 48 and the driver 49 to the Voriginal position shown vin FIGURE 1. And as Vsoon as the piston 48 is started toward its initial position by this kick, the compressed airfrom the :reservoir 51 will be able to escape through the ports 52' and Vout Vthe nose of the stapler. This airescape meanswill prevent the full force of the compressed air from acting onthe piston during its return, and soften the movement.

In commercial devices of this character, it'isgenerally desirable to provide some means for holding the driving piston'in its uppermost position. .This may be accomplished byeither a spring detent located in the nose of the stapler, or by a magnet located Ybeneath the valve seat'ZQ', or by other means known in the art. Such means are entirelyfconventiona1, and have not been shown in the `drawing accompanying this specification.

From the foregoing it is believedthat the operation of the invention'has been fully and `completely described.

Broadly considered the invention lies in the provision of a springless valve-*fone which is-actuated solely by fluid pressure and force differentials. This insures high'speed,

Aetfective operationof'the'valve irrespective .ofthe uid pressures used. v With `*specific VVreference to vpneumatic Staplers, a very eticientand economicaltoolis produced.

'Thisftoolf has the further advantage` that should a mal- `'function occur, it may be easily` and quickly repaired.

, Forrexample, lshould a defect-developin thepring valve,

the entire assembly including .the cap .330,V the post 33, the valve 37, and the insert 41 may be removed ina single unit Vand then replaced.

Havingthus described the invention,V what is claimed as new and what isy desired to be protected 'by United V1. In combination, a valve chamber having a head and a Seat, a valve element(37) reciprocableV in said cham.-

ber, a stationary memberixed in-said chamber and having `a rst portion (33)v of 'a given diameter, said valve element having'a bore (37a) inl one eindY thereof to receive said first portion, said stationary member having av secondY portion (34) of a different"diameterfand said valve eler And as. explained earlier, the greater effective surface` i varea of the top ofthe valve element 37,V asdetermined ment havinganother bore (Wb)V in the other end thereof to receive said second portion, the diameter of Ysaid first mentioned bore being different than the diameter ofi said l v second mentionedybore, and vthefetective outsideV dia-.rn-

by the'. relative-sizes "ofthe holesdand 37b in co-y operationwith thexed center post 33 and the exhaust Y ary member is providedwith apassage therethrough to atmospheragsaid stationary member yalsof being provided withorices'extending Vfronr'the outside. Vof saidr Vstationaryy 'memberto saidpassage,f'saidoric'es being located in! mand the Vexhaust valve 3ft. When. this occurs, the v Vfair in the driving cylinderrabove the piston` 43 will be vpermitted to freely escape around valve throughfV eter of said valve element being'V` constant throughout,V

Y wherebyYV when ftuid' power of equal pressure is applied to both of said ends of saidrvalveelement ata time: when* Vsaidvportions occupy theirrespectivebor'es, saidV valve element will move under thefinueucejof ,the uid power YVapplied at-that end of vsaid valveelement Vhaving the 'zoY smaller. bore therein.; n

Y v V2.,The combination of clainrl in which said stationtermediate said second portion and said head, sealing means (40) in said valve element adapted to engage said stationary member when said valve element is moved toward said head, and a sealing member (41) on said valve element, the peripheral edge at least of said 'sealing member (41) being movable with respect -to said valve element, the stationary member (33-34), sealing member (41) and sealing means (40) being arranged so that when said sealing member (41) is on said seat, said sealing means (40) is normally free of said stationary member; initial movement of said valve element towards said head bringing said sealing means (40) into sealing engagement with said stationary member while said sealing member (41) remains on said seat; further movement of said valve element toward said head serving to lift said sealing member (41) oi said seat; and whereby when said sealing means (40) is engaged with said stationary member and said sealing member (41) is off said seat, initial movement of said-valve element toward said seat will bring said sealing member (41) into contact with said seat while said sealing means (40) remains engaged with said stationary member, further movement of said valve element toward said valve seat serving tobring said sealing means (40) out of engagement with said stationary member while maintaining said sealing member (41) on said seat.

3. A springless valve comprising a valve chamber having a head (30) at one end of said chember and a valve seat (29) at the other end of said chamber, a valve element (37) reciprocable in said chamber between said head and said seat, and a sealing member (41) on said valve element adapted to seat on said valve seat, a valve post (33) fixed in said chamber, said valve element (37 having a bore (37a) in one end thereof to receive said post (33), a control member (34) fixed on said post (33), said control member (34) being larger than said post (33), and said valve element (37) having another bore (37b) in the other end thereof to receive said conltrol member (34), the diameter of said rst mentioned bore (37a) being smaller than the diameter of said second mentioned bore (37b), and the eiective outside diameter of said valve element (37) being the same at both ends thereof, whereby when fluid power of equal pressure is applied to both of said ends of said valve element (37 atta time when said post (33) and said control member V(34) both occupy their respective bores (37a and 37b),

saidvalve element (37) will move under the inuence of the fluid power applied at said one end of said valve element (37).

4. The springless valve of claim y3 in which said sealing member (41) is located on said valve element (37) adjacent said other end thereof, the peripheral edge at least of said sealing member (41) being movable with respect to said valve element (37 arelatively short distance, and means (42) to move said valve element toward said head, whereby when said sealing member (41) is on said valve seat (29) at a time when said control element (37) moves toward said head (30), said sealing member (41) will remain on said valve seat (29) during the initial movement of said valve element (37 until said control member (34) occupies said bore (37b), further movement of said valve element (37) toward said head (30) serving to lift said sealing member (41) oi said valve seat (29); and whereby when said valve element (37) is at said head (30) and said control member (34) occupies its bore (37b) while said member (41) is free of said seat (29), application of fluid power of equal pressure to both ends of said Valve element (37) will first cause said valve element (37 to move towards said seat (29) and said member (41) to engage said seat (29) While said control member (34) continues to occupy said bore (37b), further movement vof said valve element (37) v 10 in the same direction then resulting in said control member (34) leaving said bore (37b).

5. A springless valve forcontrolling the application of fluid power from a source thereof comprising: a valve chamber, a valve seat (29) at one end of said chamber, and a headA (30) `at the other end of said chamber; a valve elementm(37) slidable in said chamber between said seat and said head, said valve element having a sealing member (41) adapted to seat on said valve seat, the effective area of one end of said valve element being greater than the effective area of the other end of said valve element; first port means (28) for introducing fluid power from said source to said one end of said valve element, and second port means (15) for introducing fluid power adjacent said other end of said valve element; exhaust port control means (34) for exhausting air from outside of said valve seat and said sealing member to atmosphere; a tube (33) fixed in said head and extending from atmosphere into said valve chamber, said exhaust port control means (34) being fixed on said tube within said chamber; said one end of said valve element having a bore (37a) to receive said tube, said other end of said valve element having a bore (37b) to receive said exhaust port control means, the effective outside diameter of said valve element being one and the same at each of said ends, said bore (37a) being smaller than said bore (37 b); and means (23) to cut oil the supply of fluid power through said first port means and to exhaust luid power from said one end of said valve element to atmosphere while maintaining the application of uid poW- er through said second port means, whereby said valve element will move toward said first port means; and whereby when said means (23) is actuated to supply fluid power through said iirst port means (28)- while maintaining the application of fluid power of equal pressure through said second port means (15), said valve element (37) will move towards said valve seat (29) by reason of the area differentials caused by the effect of the difference in said bores (37a and 37b).

6. The valve of claim 5 in which said sealing member (41) is located on said valve element in the region of said other end, the peripheral edge atleast of said sealing'member being movable with respect to said valve element, and including means (41D) to seal said exhaust port means (34) when said valve element is moved toward said rst port means, said sealing member (41) remaining on said valve seat until said means (40) seals said control means (34) whereby preventing any pressure loss to atmosphere, and whereby continued movement of said valve element will lift said sealing member from said valve seat and immediately expose all of the elective area of said other end of said valve element to the fluid power introduced through said second port means. Y

7. A springless fluid valve for use with a source of fluid under pressure comprising a valve chamber; a valve seat at one end of said chamber; a valve piston slidably received in said chamber, one end of said valve piston being adapted to seat against said valve seat, said valve'pis-y ton having a single effective outside diameter and a passage extending therethrough; means cooperating with said passagev in said` valve piston whereby the other end of said valve piston has a greater effective surface area than said one end of said valvetpiston; said valve chamber having a first port in communication with said uid under pressure located adjacent said other end of said valve piston, said valve chamber having a second port in communication with said tluid under pressure located adjacent said one end of said valve piston; valve means for controlling the flow of said iiuid under pressure `to said first port; and vexhaust means associated with said valveu chamber adjacent said other end of said valve piston; whereby when said fluid under pressure is applied to both ends of said valve piston the yresultant force is ,operative to seat said oneY end of said valve'pston against said valve seat. v

References Cited by the Examiner. UNITED STATES PATENTS Murphy etral. 137--6275 CampbellV IS7-6.25.6 Powers 91-461 Goldring et a1. 91-,461

Wandel 91-461 References Cied bythe Applican UNITEDY STATES PATENTS 267,027 1\1/82 shaw. Y k2,677,933 5/54 Hopkinson.

2,722,234 11/55 W. B. MacGeorge et al. v

3,106,136V '10/63 A. Langaset al. 3,147,670 9/64 i H. I. Spencer. Y 

1. IN COMBINATION, A VALVE CHAMBER HAVING A HEAD AND A SEAT, A VALVE ELEMENT (37) RECIPROCABLE IN SAID CHAMBER, A STATIONARY MEMBER FIXED IN SAID CHAMBER AND HAVING A FIRST PORTION (33) OF A GIVEN DIAMETER, SAID VALVE ELEMENT HAVING A BORE (37A) IN ONE END THEREOF TO RECEIVE SAID FIRST PORTION, SAID STATIONARY MEMBER HAVING A SECOND PORTION (34) OF A DIFFERENT DIAMETER, AND SAID VALVE ELEMENT HAVING ANOTHER BORE (37B) IN THE OTHER END THEREOF TO RECEIVE SAID SECOND PORTION, THE DIAMETER OF SAID FIRST MENTIONED BORE BEING DIFFERENT THAN THE DIAMETER OF SAID SECOND MENTIONED BORE, AND THE EFFECTIVE OUTSIDE DIAMETER OF AID VALVE ELEMENT BEING CONSTANT THROUGHOUT, WHEREBY WHEN FLUID POWER OF EQUAL PRESSURE IS APPLIED TO BOTH OF SAID ENDS OF SAID VALVE ELEMENT AT A TIME WHEN SAID PORTIONS OCCUPY THEIR RESPECTIVE BORES, SAID VALVE ELEMENT WILL MOVE UNDER THE INFLUENCE OF THE FLUID POWER APPLIED AT THAT END OF SAID VALVE ELEMENT HAVING THE SMALLER BORE THEREIN.
 2. THE COMBINATION OF CLAIM 1 IN WHICH SAID STATIONARY MEMBER IS PROVIDED WITH A PASSAGE THERETHROUGH TO ATMOSPHERE, SAID STATIONARY MEMBER ALSO BEING PROVIDED WITH ORIFICES EXTENDING FROM THE OUTSIDE OF SAID STATIONARY MEMBER TO SAID PASSAGE, SAID ORIFICES BEING LOCATED INTERMEDIATE SAID SECOND PORTION AND SAID HEAD, SEALING MEANS (40) IN SAID VALVE ELEMENT ADAPTED TO ENGAGE SAID STATIONARY MEMBER WHEN SAID VALVE ELEMENT IS MOVED TOWARD AI DHEAD, AND A SEALING MEMBER (41) ON SAID VALVE ELEMENT, THE PERIPHERAL EDGE AT LEAST OF SAID SEALING MEMBER (41) BEING MOVABLE WITH RESPECT TO SAID VALVE ELEMENT, THE STATIONARY MEMBER (33-34), SEALING MEMBER (41) AND SEALING MEANS (40) BEING ARRANGED SO THAT WHEN SAID SEALING MEMBER (41) IS ON SAID SEAT, SAID SEALING MEANS (40) IS NORMALLY FREE OF SAID STATIONARY MEMBER; INITIAL MOVEMENT OF SAID VALVE ELEMENT TOWARDS SAID HEAD BRINGING SAID SEALING MEANS (40) INTO SEALING ENGAGEMENT WITH SAID STATIONARY MEMBER WHILE SAID SEALING MEMBER (41) REMAINS ON SAID SEAT; FURTHER MOVEMENT OF SAID VALVE ELEMENT TOWARD SAID HEAD SERVING TO LIFT SAID SEALING MEMBER (41) OFF SAID SEAT; AND WHEREBY WHEN SAID SEALING MEANS (40) IS ENGAGED WITH SAID STATIONARY MEMBER AND SAID SEALING MEMBER (41) IS OFF SAID SEAT, INITIAL MOVEMENT OF SAID VALVE ELEMENT TOWARD SAID SEAT WILL BRING SAID SEALING MEMBER (41) INTO CONTACT WITH SAID SEAT WHILE SAID SEALING MEANS (40) REMAINS ENGAGED WITH SAID STATIONARY MEMBER, FURTHER MOVEMENT OF SAID VALVE ELEMENT TOWARD SAID VALVE SEAT SERVING TO BRING SAID SEALING MEANS (40) OUT OF ENGAGEMENT WITH SAID STATIONARY MEMBER WHILE MAINTAINING SAID SEALING MEMBER (41) ON SAID SEAT. 